Dolfi 10 m (32,4') : a modern daysailer to enjoy classic sailing

Dolfi wants to be in the tradition of fine elegant keelboats with a small cabin, inaugurated by the Skerry cruisers in the 1920s, which has produced very popular monotypes like Hai and Malar, and of which sailing specific qualities remain highly appreciated by amateurs. Dolfi offers a renewed version of this program, with a more modern hull and sail plan, with the comfort of a larger cockpit and of a cabin with sanitary, for day sailings and when occured for weekend for 2 people. Dolfi hull, with a length of 9.90 m (32,5') for a width of 2.4 m (7,9'), shows classic lines and slenderness proper to this tradition.

I am pleased to share with you the project file here attached, many thanks in advance for your interest and your comments.

Absolutely gorgeous! For me ,if I were to want such a boat I'd like a super comfortable cockpit with somewhat high seat backs. Best of luck with this beautiful project!

Click to expand...

Dear Doug, many thanks I have not detailed the cockpit arrangement too much, as several solutions of seats, winchs position, etc ... are possible according to the request of first customers and their sailing objective : sports or quiet ride. I also received a remark about the rudder, not deep enough according to current standards.

Dolfiman, I do like the lines and layout on this boat. I concur on the rudder length. A pinch longer would help it in rough seas where it may otherwise not have enough bite to maintain good control. Here's a slightly smaller one as an example.

On the LA-28 yes...definitely an option. The Dolphi 10m has a narrower stern though. A single, slightly longer rudder would do.

I love day sailors, but my heart is in a larger boat for longer voyages. I could only tolerate bumping my head in the short cabin just once. Then that would be it. No more bloody scalps. Time for a bigger boat!

Yes I like these so called modern classic yachts for their timeless lines and offering pleasant classic sailings as long as you are not obsessed by speed in downwind conditions, it is worth to cross these classic proportions with modern (underwater) hull, materials, sails and hydrodynamic appendages. It is a growing market, there are already a lot of designer/shipbuilder on this line, although

their designs are usually proposed with a luxurious building and so at a high price. E​

On wide transom : here there is a frontier between the "classic" and the "modern", of course a beamy with wide transom can offer a lot more volume inside (possibility of a rear cabin) and more cockpit surface. But they are not very elegant with their vertical bow, their bowsprit, their attitude when upwind sailing, usually nose down + the windward rear side of the cockpit very high above the water. These design fit more for cruising with high percentage of downwind conditions. For the daysailing programme of Dolfi, I opted for a mid-sized transom within slender proportions by esthetic choice, just large enough to have a more confortable cockpit and cabin that the historic skerry cruisers, and still compatible with one rudder.

When I hesitated on that point, finally I developed a specific transformation of the hull lines in Gene-Hull (my thread in the Software forum) to help the iteration process, I called it "transformation Alfa" . That transforms a given hull in a wider one by a sheer line rotation of half-angle Alfa with the bow end as center of rotation, while keeping constant the longitudinal x values (it is probably more clear with the sketches showed in Gene-Hull user guide here reminded). So, you can move from a classic slender hull to a more beamy together with a wider transom, by changing only one parameter, Alfa. And for Dolfi, after testing several Alfa, I choose an average solution. Examples here attached with the Dolfi linesplan.

The cabin is small, but sufficient as shelter and for a toilet which is the N° 1 specification that I collected for this daysailing programme. H 1,25 m, I agree it is not a lot but sufficient. I can eventually increase a bit that figure with higher freeboards and cabin, and a bit more overall displacement.

Hi Dolphiman, fine job on the hull iterations. I like your choice...it's a good balance leaning on the beamier side for improved stability & seaworthiness. I concur on the desire for classic lines too. They are much more pleasing to the eye. The racing mathematicians who push for modern lines are obviously seeking max speed and the hull features that go with them. The wide, boxy stern also gives improved control on the helm. You don't appreciate that until you realize you can steer with one finger on the helm for hours. As the boat heels over and catches that sharper stern edge the steering becomes easier...you can ride that fine edge like a surfboard on a wave. The benefit is a helmsman can stay on deck for longer periods...and perhaps provide an edge in winning a long distance race.

Of course, if you've got a canting keel to keep that heeling angle you can get there with that approach as well. If not, the only other option is to put crew & + movable ballast down below decks. Either way you've got to get the weight & balance on the high side locked in.

On the 1.25m headroom in the cabin, for a day sailor as long as a big person can crawl easily & take a nap that's the best you can do. I don't know what the interior looks like for Dolphi, but be sure there is absolutely nothing that will cut into a persons scalp. Use large radius turns with smooth edges all around and the crew will be very thankful. The exterior & interior trim should be complimentary (smooth, sexy curves and with as much wood trim as you can spare). Please keep us posted on further updates.

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